Completion rate is the number that tells you whether a form is working. Most forms that underperform are not badly designed; they contain one or two of the patterns below, and each one takes a few percent off the top.
1. The phone number on page one
Asking for a phone number before you have earned it is the single most expensive field in most forms. Move it to the end, make it optional, or replace it with a question about how the respondent prefers to be contacted.
2. Dropdowns with more than seven options
Past seven options, a dropdown becomes a search problem. Use a searchable select, split the list into a two-step choice, or turn the most common options into buttons and hide the long tail behind "Other".
3. Error messages that describe the rule, not the fix
"Invalid input" tells the respondent they are wrong. "Use the format DD/MM/YYYY" tells them what to do. Every error state should contain the fix.
4. Required fields that are not really required
If a blank answer would not stop you processing the response, the field is optional. Every unnecessary required field is a place for the respondent to give up.
5. Progress indicators that lie
A progress bar that jumps from 20 percent to 90 percent because of a conditional path is worse than no bar at all. If the form branches, show steps rather than percentages.
6. Asking for the same thing twice
Name on page one, name again on the signature page. Respondents notice, and they read it as carelessness. Prefill from earlier answers or hidden fields instead.
7. No way back
Respondents change their minds. If the form does not let them go back to an earlier answer without losing everything after it, a good share of them will abandon rather than restart.
None of these is a redesign. Fix one a week, and watch the number move.
